SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd00930f8a99c578612b88123f4207635579e0ebbc9116f7d1e2a1ec98906751' 
  AND token = '/zEgiHTJfRPVIyUm4nl02mPWgCY6D7ViQ4i5jTRR+lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}